1. Field of the Invention
The present invention relates to a light emitting element and a method for producing the same, including an electronic tube which utilizes the discharge light emission of at least one of a gas and a light emitting substance enclosed in a formed product made of, for example, a glass material.
2. Description of the Related Art
In general, the light source, which utilizes the discharge light emission of at least one of the gas and the light emitting substance enclosed in a tube made of glass, includes electronic tubes such as mercury lamps, fluorescent tubes, sodium lamps, carbon arc lamps, zirconium discharge lamps, neon tubes, and flash discharge lamps.
The electronic tube as described above is manufactured, for example, such that an anode bar is fused to one end of a cylindrical glass tube, and then a cathode bar is fused to the other end of the glass tube in a predetermined gas atmosphere (atmosphere containing the gas to be enclosed) to enclosed the predetermined gas in the glass tube.
It is contemplated that such an electronic tube is utilized to display, for example, images and characters at the outdoor.
In such a situation, it is conceived that a large number of electronic tubes are arranged so that the light is selectively emitted from the electronic-tubes. However, the respective electronic tubes exist as single members. Therefore, when the large number of electronic tubes are arranged, the scale is inevitably large. As a result, problems arise in that the installation space is enlarged, the wiring operation is complicated, and the production cost becomes expensive.
Under the circumstances, it is expected that the electronic tube itself is allowed to have a miniature size. However, if the electronic tube is miniaturized, then the distance between the anode and the cathode is decreased, and the pressure at the inside of the glass tube is further increased during the light emission. Therefore, it is necessary to increase the strength of the glass tube in association with the miniaturization of the electronic tube.
The present invention has been made taking the foregoing problems into consideration, an object of which is to provide a light emitting element which makes it possible to simultaneously realize the integration and the miniaturization of the electronic tube and present the display expression for information transmission at a high brightness.
Another object of the present invention is to provide a method for producing a light emitting element, in which it is possible to easily produce the light emitting element which makes it possible to simultaneously realize the integration and the miniaturization of the electronic tube and present the display expression for information transmission at a high brightness.
According to the present invention, there is provided a light emitting element formed by confronting at least two glass members with each other in a predetermined atmosphere and thermally gluing them under a pressure; the light emitting element comprising a cavity enclosed with at least one of a gas and a light emitting substance at its inside; and mutually confronting electrodes provided for the cavity interposed therebetween.
The cavity, in which at least one of the gas and the light emitting substance is enclosed, is formed in the formed product which is manufactured by thermally gluing the glass members under the pressure. The electric power is applied to the electrodes which are opposed to one another with the cavity interposed therebetween. Thus, the discharge light emission is effected by at least one of the gas and the light emitting substance enclosed in the cavity. That is, one cavity functions as one electronic tube.
Therefore, when a large number of electronic tubes are integrated with each other in order to make display for information transmission, it is convenient that a large number of cavities are integrated with each other. In the present invention, the cavity is formed by thermally gluing the glass members. Therefore, it is possible to integrate the large number of cavities at a high degree of integration. Accordingly, it is also possible to easily realize the miniaturization thereof.
As described above, according to the light emitting element concerning the present invention, it is possible to simultaneously realize the integration and the miniaturization of the electronic tube and present the display expression for information transmission at a high brightness.
In the arrangement described above, it is also preferable that the electrodes are constructed by lead wires fixed on a surface at which the glass members contact with each other. Alternatively, the electrodes may be constructed by thin films formed by printing on a surface at which the glass members contact with each other. Especially, when the electrodes are constructed by the thin films, then the labor for wiring arrangement can be eliminated, and it is possible to simplify the production steps. Further, the positioning can be easily performed in order to confront the electrodes with each other with the cavity interposed therebetween.
In the arrangement described above, it is also preferable that the glass member to be used has a bending strength of not less than 1000 kgf /cm2.
For example, in the case of the light emitting element in which argon, mercury or the like is enclosed in the cavity, the glass member having a bending strength of about 1000 kgf /cm2 is used. In the case of the light emitting element in which the gas such as xenon capable of obtaining a high brightness is enclosed, the glass member having a bending strength of about 3000 kgf/cm2 is preferably used.
In general, in order to improve the resolution of the display expression, it is necessary to increase the number of cavities which function as electronic tubes. However, considering the miniaturization in such a situation, it is to conceived that the respective cavities are reduced in size. If the size of the respective cavities is reduced, the pressure in the cavity is increased during the light emission in accordance therewith. However, when the glass member satisfies the condition for the bending strength as described above, the formed product is obtained, which is sufficiently capable of withstanding the pressure in the is cavity. Thus, it is possible to avoid the inconvenience such as the light emission defect.
In the arrangement described above, it is also preferable that the glass member to be used has a coefficient of thermal expansion which is substantially zero or which is near to a coefficient of thermal expansion of the electrode. In this arrangement, the heat resistance is excellent, and the light emitting element is advantageous in resistance to the heat cycle relevant to the repetition of discharge light emission of at least one of the gas and the light emitting substance enclosed in the cavity.
According to another aspect of the present invention, there is provided a method for producing a light emitting element, comprising a first step of providing electrodes on a contact surface of a glass member; and a second step of confronting respective contact surfaces of at least two of the glass members with each other so that they are thermally glued under a pressure in a predetermined atmosphere to produce the light emitting element comprising a cavity enclosed with at least one of a gas and a light emitting substance at its inside; and mutually confronting electrodes provided for the cavity interposed therebetween.
Accordingly, it is possible to simultaneously realize the integration and the miniaturization of the electronic tube, and it is possible to present the display expression for information transmission at a high brightness.
In the present invention, in the first step described above, it is preferable that the electrodes are provided by fixing lead wires on the contact surface of the glass member. It is also preferable that the electrodes are provided by forming a thin film by means of printing on the contact surface of the glass member.
It is also preferable that a glass member having a bending strength of not less than 1000 kgf/cm2 is used as the glass member. It is also preferable that a glass member having a coefficient of thermal expansion which is substantially zero or which is near to a coefficient of thermal expansion of the electrode is used as the glass member.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.